The invention relates to a device for ensuring safe movement of a moving part. The lampholder adapter includes a rotatable locking disk member set in a base assembly for receiving the end-prongs of a fluorescent lamp. Stimulated Raman scattering from the interaction between the excited target region and the laser probe pulse is detected. A second voltage is generated between the second region and the third region to cause the carriers move across the second domain from the second region to the third region. The front cover covers the tray with each of the air nozzles received in one assembling hole, and the air nozzles are capable of blowing air against the lenses causing the dust deposited on the outer surface of the lenses to be blown away through the through holes.